Service Engine Soon Light: What does it mean?

This is one of the first things you should check if the service engine light comes on. A loose gas cap, or one that has a crack, will cause fuel vapors to leak and this could trick the Engine Control Module into thinking there’s a problem. This can increase emissions and increase fuel consumption, so it’s better to deal with it as soon as possible.

Depending on the type of car you drive, the service engine soon light could simply indicate what the name says: you are a week or so past the car’s next scheduled oil change. That might not be too urgent. However, it could also mean the car’s oil level has dropped critically low, so have it checked as soon as possible.

Sometimes an engine warning light can come on for something as simple as contaminated gas. This should go away after the car has worked through one or two tanks of good gas, but if you’re unsure, have the car hooked up to a diagnostic reader to check.

The ratio of gasoline to oxygen in any modern vehicle is very important. When that goes wrong, the car will not run optimally. Too little oxygen can harm the engine because the mix includes too much gasoline. Too much oxygen, on the other hand, could cause poor engine performance and even engine damage. In later stages, a malfunctioning oxygen sensor could also negatively affect the catalytic converter or the spark plugs. 

Any car’s wires and spark plugs wear out as time goes by and sooner or later they have to be replaced. If your car’s spark plugs or wires become faulty, it could impact the combustion process. You may notice difficulty accelerating, rough idling, hard starts, or misfiring, which will trigger the service engine soon light to come on.

This is a critical piece of equipment in any modern vehicle. Its job is to measure the air volume passing through the car’s air filter. Afterward, it sends a message to the onboard computer about how much gasoline the engine needs. The amount of fuel needed depends on the amount of air that enters the engine.

A malfunctioning mass airflow sensor will cause the car to stall and your fuel consumption to increase. Delaying the replacement of the mass airflow sensor can cause damage to the spark plugs. More seriously: it can damage the catalytic converter, which may be a costly repair.

If you live in the Pomona region of California and your car’s service engine soon or check engine light comes on, you can’t do much better than visiting Taylor Co Automotive Services. We’ve been doing European and US car repairs for the past 32 years.